Immersing contaminteo



March 3, 1964 P. A. J. CHARREAU 3,123,494

PROCESS FOR THE DRY CLEANING AND WATERPROOFING OF FABRICS Filed NOV. 9, 1959 IMMERSING CONTAMINTEO TEXTILE ARTICLES IN A DRY-CLEANING BATH CONTAINING POLYSILOX'ANE AGITATING smo ARTICLES IN SAID BATH To CAUSE FOAMING SEPARATING THE CLEANED ARTICLES FROM THE SOLVENT-AND FOAM-CONTAINING CONTAMINANT REMOVING SOLVENT FROM CLEANED ARTICLES CONTACTING THE CLEANED ARTICLES WITH*F'LOWING STEAM AT AT LEAST IOO'C INVIINTQR PAUL AUGUSTE JOSEPH CHARREAU ATTORNEY United States Patent C 3,123,494- PRUCESS FGR THE DRY KILEANENG AND WATElElRQQFlNG F FABRHCS Paul Auguste Joseph Charreau, 23 Rue des Chaplier's, Lannion (Cotes du Nord), France Filed Nov. 9, 1959, Ser. No. 851,512 tClahns priority, application France Get. 3, 1958 5 Claims. (Cl. 117-452) This application is a continuation-in-part application of my US. application Serial No. 842,932, filed September 28, 1959.

A dry cleaning is usually understood to mean a cleaning which is effected without water or aqueous substances, by means of anhydrous solvents, which for practical purposes are selected from the class of hydrocarbons and chlorinated hydrocarbons.

As a matter of fact for the last few years a series of operations including the use not only of organic solvents but also of water and soap have been carried out for cleaning purposes and are still referred to as dry cleaning. Usually in modern installations, a degreasing treatment by means of an organic solvent, then a treatment with a solvent containing Water and soap with a view to removing a portion of lean impurities, and finally a rinsing to remove soap and water traces are eifected successively in the same machine.

While satisfactory results are indeed obtained, clothes are however subjected to severe conditions which in particular result in removing dressing. For that reason ironmg is very delicate to perform and requires the utmost care. stiffening fabrics and linings have lost their firmness and there is the hazard of finding shrunk or felted articles among clothes subjected to such treatrnents.

It is also known that with a view to waterproofing clothes, silicones tend to supersede waxes and other waterproofing agents employed in the past. The use of silicones for waterproofing purposes requires a number of indispensable precautions. In particular, for the articles to be waterproofed it is considered necessary that they should have been dry cleaned previously with extremely clean solvents which should be strictly anhydrous and unaccompanied with soap. By reason of the hydrolytic eilect of water it is necessary to remove any trace of moisture from the articles before subjecting said articles to a waterproofing treatment, and for that purpose to dry the same carefully in a hot air stream and to avoid any storing in a damp atmosphere such as that in rooms where ironing is performed. In practice, an initial dry cleaning is efiiectecl without water not soap, then a dry cleaning treatment is carried out with an anhydrous solvent to which a silicone is added.

I have now found contrary to any expectation that silicones usually employed as waterproofing agents produce an extremely effective cleaning action, and that foams which they develop upon stirring and the presence of which was considered heretofore as a drawback and as something to be rigourously avoided, should on the contrary be sought with a view to removing impurities thoroughly.

Accordingly I provide a process for dry cleaning wherein contaminated articles to be cleaned are contacted with a waterproofing silicone, and stirring to cause frothing of the silicone is produced.

3,123,494 Patented Mar. 3, 1%64 The waterproofing silicones to be employed according to this invention are more particularly those described in the work Silicones and Their Uses by Rob Roy Mac- Gregor (McGraw-Hill, publishers, New York), and in the present instance organopolysiloxanes, inter alia dimethylpolysiloxanes comprising the characteristic group:

(III-Is -si-0 CH3 and methyl hydrogenopolysiloxanes comprising the characteristic group:

CIII

in the presence or absence of catalysts, which silicones may be polymerised at temperatures ranging from ambient temperature to more than 100 C. It is particularly recommended to employ as cleaning solvent silicones in the form of compositions which are mixtures of dimethylpolysiloxane or methylhydrogenopolysiloxane resins (i.e. cross-linked polymers in which the ratio between the numer of methyl radical and the number of silicon atoms is below 2, more particularly from 1.4 to 1.7), dimethylpolysiloxane or methylhydrogenopolysiloxane fluids (i.e. linear or substantially linear polymers) and alkyl titanates having from 1 to 10 carbon atoms, more especially butyl titanate (catalysts), or solutions thereof in a hydrocarbon or in a chlorinated hydrocarbon of the type hereinbefore described. The amount of alkyl titanate may vary from 1 to 35 percent by weight with respect to the organopolysiloxanes. The solutions may consist of about 50 percent by weight of said hydrocarbon or chlorinated hydrocarbon and about 50 percent by weight of the mixture of resin, fluid and alkyl titanate above mentioned. Compositions of this type are described in French Patents Nos. 1,054,423 and 1,049,930, both in the name of Union Chimique Beige SA. A suitable composition is that marketed by the Company Rhone-Poulenc under the name Rhodorsil hydro'fugeant 85 G For practical purposes the silicone or silicone composition may be diluted in any usual dry cleaning solvent. The solvent may be more especially a compound or a mixture or" compounds of the class of hydrocarbons and chlorinated hydrocarbons which are employed or have been proposed for dry cleaning. Typical solvents are trichloroethylene (RP. 87 C.), perchloroethylene (B.P. 119 (3.), carbon tetrachloride (BF. 76 C.), o-dichlorobenzene (Bl 175 C.), benzene (BP. C.), toluene (Bl 111 C.), m-xylene (BE. 139 C.), sol-vent naphtha (BF. 12G-165 (1.), a light petroleum fraction (BP. 160 0), white spirits and notably that having a boiling range of 175 C., and the variety having a higher boiling range known under the name Dilutine. Perchloroethylene and trichloroethylene, which are very eftective for dry cleaning are of outstanding interest, particularly as representative of the class of uninflammable solvents, or solvents which are inflammable only with difficulty.

The accompanying drawing illustrates the order of steps of the method.

Any proportion of silicone or silicone composition as 3 above defined in the mixture thereof with a solvent hydrocarbon of chlorinated hydrocarbon solvent, varying from about 1 percent to the neighborhood of 100 percent by weight, may be employed.

Although it is sufficient for practical purposes, to place the articles to be cleaned, to whatever extent they are contaminated, directly into contact with the silicone composition or mixture thereof with a solvent, it is possible according to this invention firstly to carry out a previous cleaning treatment with an anhydrous solvent whereby the articles are at least partly degreased, then to remove solvent to a more or less large extent for example by a simple draining or possibly by wringing or centrifuging, and then to treat the articles with silicone.

In carrying out this invention, the articles may be placed in a silicone composition or mixture thereof with a solvent, or conversely the articles may be placed in a cleaning vessel, then the silicone composition or mixture thereof with a solvent added. As to the amount of silicone composition or mixture thereof with a solvent to be em ployed it is only necessary for the article to be cleaned to be wetted by the same.

For practical purposes, it is advantageous to work in a conventional dry cleaning machine, in particular of the type having a double wall barrel or drum whose inner wall is perforated and which is supported for continuous rotation or for alternate rotations in one direction and the opposite direction about the axis thereof. No heat supply is required.

As the drum is in operation, there is produced a copious foam which carries impurities along therewith and egresses through the drum perforations, said impurities collecting on the surface of the foam. According to the conditions, the period of treatment may vary from a few minutes to about half an hour or more. As soon as cleaning is considered to be sufficient, the contaminated liquid is removed for example with a pump, and liquid is removed from the articles for example by centrifuging, with a view to recovering a more or less large portion of the liquid retained in the cleaned articles. Where in addition to the cleaning effect a waterproofing effect is sought, centrifuging is carried out only to the extent that a residual amount of to g. of pure silicone per kg. of textile, namely from 2 to 3 percent by weight, is left in the articles. However draining may be effected more thoroughly where only a very slight waterproofing is sufiicient; anyhow such a Waterproofing is desirable because it imparts a very pleasant feeling to the articles.

With a view to regenerating the used silicone composition or mixture thereof with a solvent it is enough to filter the same for example on a cotton filter, possibly after having added an adsorbing material such as adsorbing coal or infusorial earth thereto. The impurities and as the case may be the adsorbing material are retained on the filter, and there is recovered a silicone composition or mixture thereof with a solvent which is entirely freed from dust, and which is clean and suitable for reuse.

As to the cleaned articles, any solvent remaining therein may be removed by placing said articles in an air stream initially heated to about 4G C. and the tempera ture of which is raised gradually to 120-130 C. for example. That treatment may be carried out in the same apparatus as that which has been employed for effecting the waterproofing cleaning where the apparatus, as are many modern types thereof, is equipped for drying with hot air travelling through a cycle which comprises a condenser where organic solvents are liquified and can be recovered.

a As main advantages of the process according to the invention, clothes are subjected to one treatment; they are contacted neither with soap nor with water; none of the drawbacks of shrinking and felting is met; additional posts for wetting and for removal of stains are practically needless, and delicate articles the colour of which might fade in the presence of water may be cleaned partly or completely without damage, by reason of the properties of silicones.

I have further found that it is possible in an extremely simple fashion to produce a kind of ironing effect on articles which have been Waterproofed by means of a silicone according to this invention; that effect may be produced in the apparatus where the articles have been successively dry cleaned and waterproofed then dried in hot air under conditions providing for silicone polymerization.

The ironing effect is produced by contacting the silicone waterproofed articles with flowing steam at a temperature of at least C. in the earlier stage of contact with steam, that is to say while the articles are still at a lower temperature than steam, a condensation takes place on the articles but the water produced rolls as pearls and is not retained by the articles since the articles have been waterproofed. The articles thus treated with steam are smoothed out and wrinkles are removed, so that final ironing is simplified to a considerable extent or may even be omitted.

What I claim is:

1. A process for dry-cleaning contaminated textile articles which comprises immersing said articles in a drycleaning bath comprising (1) an anhydrous liquid selected from the group consisting of hydrocarbon dry-cleaning solvents, chlorinated dry-cleaning solvents, and mixtures thereof, and (2) a methylpolysiloxane, agitating said articles in said bath sufliciently to cause the production of a body of foam on the surface of said bath, wh reby soluble contaminants in said articles are dissolved by said solvent and insoluble contaminants are collected in said foam, separating the thus-cleaned articles from the contaminant containing solvent and foam, removing adherent solvent from said cleaned articles so as to leave from 2 to 3 percent by weight of said organopolysiloxane therein and drying said garments.

2. A process according to claim 1 in which the polysiloxane is a mixture of a resin selected from the class consisting of dimethyl polysiloxane resins and methylhydrogen polysiloxane resins, and at least one fluid selected from the class consisting of liquid dimethyl polysiloxane and liquid methyl hydrogen polysiloxane.

3. A process according to claim 1 in which the drycleaning bath includes an alkyl titanate containing from 1 to 10 carbon atoms.

4. A process according to claim 1 in which the cleaned articles are contacted with flowing steam at a temperature of at least 106 C. to smooth out the said articles and to remove wrinkles therefrom.

5. A process according to claim 1 in which about 50% by weight of the dry-cleaning bath is a methyl polysiloxane.

References (Iited in the file of this patent UNITED STATES PATENTS 1,704,604 Hatfield Mar. 5, 1929 2,077,857 Seaton Apr. 20, 1937 2,774,690 Crockett et al. Dec. 18, 1956 2,933,411 Novak Apr. 19, 1960 

1. A PROCESS FOR DRY-CLEANING CONTAMINATED TEXTILE ARTICLES WHICH COMPRISES IMMERSING SAID ARTICLES IN A DRYCLEANING BATH COMPRISING (1) AN ANHYDROUS LIQUID SELECTED FROM THE GROUP CONSISTING OF HYDROCARBON DRY-CLEANING SOLVENTS, CHLORINATED DRY-CLEANING SOLVENTS, AND MIXTURES THEREOF, AND (2) A METHYLPOLYSILOXANE, AGITATING SAID ARTICLES IN SAID BATH SUFFICIENTLY TO CAUSE THE PRODUCTION OF A BODY OF FOAM ON THE SURFACE OF SAID BATH, WHEREBY SOLU- 